Apparatus for the production of pulp.



G. A. STEBBINS.

APPARATUS FOR THE PRODUOTION OF PULP.

APPLICATION FILED APR. 15, 1910.

Patented Aug. 13, 1912.

Witnesses Attorneys COLUMBIA PLANOGIAPN CO" WASHINGTON. D C

UNITED STATES PATENT OFFICE.

GEORGE A. STEBBINS, OF WATERTOWN, NEW YORK.

APPARATUS FOR THE PRODUCTION OF PULP.

To all whom it may concern:

Be it known that I, Gnonon A. Srnnnnvs, a citizen of the United States,residing at lVatertown, in the county of J e'tlerson and State of NewYork, have invented a new and useful Apparatus for the Production ofPulp, of which the following is a specification.

This invention relates to a process and apparatus for the production ofpulp such as is used in the manufacture of paper and the like.

l'leretofore, two methods have been employed in the production of pulp.These methods are known as the direct and the indirect. The directmethod is carried out by feeding the chips or other material to thedigester and then feeding steam to them while in the digester so as tocook them by the direct action or contact of the steam. This directmethod, while it is rapid in its results, is attended by certaindisadvantages. The condensation of the steam dilutes the acid liquor,and in order to counteract this dilution, the acid liquor is usuallymade stronger than is necessary to produce the best effects, and theresulting pulp is accordingly of an inferior character. The indirectmethod is carried out by heating the product in the digester in anindirect manner such for example, as by supplying the steam to pipes orcoils located around the interior of the digester so that the heat fromthe steam is radiated to the material in the digester, but the steamitself does not com-e in direct contact therewith and consequently doesnot dilute the acid liquor. This method has the advantage, over thedirect method, of producing a very much better grade of pulp, for thereason that a weaker acid liquor can be employed and the quality of thepulp is accordingly not injuriously afi'ected. The indirect method,however, has the disadvantage that it c0n sumes a very much greaterperiod of time than the direct method. In fact, the gain resulting fromthe superior grade of pulp produced by the indirect method, ispractically off-set by the loss occasioned by the great length of timenecessary for carrying out the method. It is apparent therefore that themanufacturer of pulp has been put to the necessity of deciding whetherhe would sacrifice the quality of his pulp by using the direct method orsacrifice his time by using the indirect method.

Specification of Letters Patent.

Application filed April 15, 1910.

Patented A11 13, 1912.

Serial No. 555,644.

The object of the present invention is to provide a process andapparatus by means of which the rapidity of the direct method and thesuperior product of the indirect method may be approximated.

\Vith the foregoing and other objects in view which will appear as thedescription proceeds, the invention resides in the process and apparatushereinafter described and claimed, it being understood that changes inthe embodiment of invention herein disclosed can be made within thescope of the claims without departing from the spirit of the invention.

In the accompanying drawings forming part of this specification :Thcfigure is a vertical section of the novel form of apparatus by means ofwhich the process of the present invention may be carried into effect.

The process of the present invention, briefly outlined, consists inrapidly raising the temperature of the products in the digester to thedesired degree wit-h the aid of the direct method, and then maintainingthe product at said temperature, by means of the indirect method, untilthe pulp is produced. The resulting pulp is very much superior to thatresulting from the direct process and almost as superior as thatobtained from the indirect method, and the time consumed is very muchshorter than that necessitated by the indirect method, and only three orfour hours longer than that consumed by the direct method. The presentprocess, therefore, approximates the advantages of both the direct andthe indirect methods, without the disadvantages.

of either.

The novel form of apparatus, by means of which the process of thepresent invention can be carried into effect, includes a digester orshell 1 having the usual acid proof lining 2. Arranged at the upper endof the digester is the entrance opening 3. At the lower end of thedigester is the T 4 by means of which the pulp may be blown or drawn offby steam after the process has been completed. Extending through thedigester 1 and lining 2 at any suitable point is a bushing 5 with whichis connected a steam pipe or radiator 6 supported in any suitable mannersuch for example as by means of the spider arms 7 and 8 suitablyconnected with the interior of the digester in such manner as not tointerfere with the action of the acid proof lining. Steam is admitted tothe radiator 6 in any suitable manner such for example as by means ofthe pipe 8 located on the outside of the digester. The water ofcondensation is withdrawn from the pipe 6 in any suitable manner such asby means of the valve 9. Extending longitudinally through the radiator 6is a pipe 10 which is supported in any suitable manner as by means ofthe spider arm 11. The pipe 10 terminates adjacent the upper end of theradiator 6 and is open at that point. At its lower end the pipe 10extends through a bushing 12 and is provided with a valve 13. The pipe10 is used to draw off any air which may be trapped in the upper end ofthe radiator 6. Steam is admitted to the interior of the digester in anysuit-able manner such as by means of the inlet l t of the T 4. The novelform of apparatus described, or any other form of apparatus fallingwithin the terms of the following claims is used, in carrying out theprocess of the present invention, in the manner which will now bedescribed. The digester is filled with the material which is to beconverted into pulp and the acid liquor. The cover plate atthe top (notshown) is secured in position and steam is then admitted in the usualmanner at the point it until a pressure of approximately 85 pounds isreached. In the meantime, steam has been admitted at 8 to the radia--tor 6 for the purpose of aiding and hastening the raising of thepressure to 85 pounds. l/Vhen this pressure is reached, the steam at 14is cut cit and the steam at 8 is maintained so as to continue thecooking process within the digester until the contents of the same havebeen entirely treated, after which the pulp is discharged at 4.

It is found in practice that the contents of the digester can be readilyraised to the temperature desired in the manner described by supplyingthe steam directly and indirectly to the digester, and after saidtemperature has been reached, the indirect action of the steam in theradiator 6 serves rapidly to complete the process.

The form of apparatus herein described, has many advantages. The costlyarrangement of supporting coils adjacent the shell of the digester isentirely avoided. Old forms of direct method digesters can. be readilyequipped with the improvements of the present invent-ion in order toadapt them for use in carrying out the methods herein disclosed. in theevent that the di gester gets out of order, it can be readily repairedwithout necessitating the great loss of time and labor which resultswhen it is necessary to repair a digester which is equipped withinternal coils. The time during which coil digesters are thrown out ofoperation pending repairs is, a very considerable item, and the loss inlining is also material in removing and replacing coil arrangements.These disadvantages are almost entirely obviated in the present form ofapparatus.

l/Vhat is claimed is 1. A vertically disposed digester having acentrally located vertically extending ra diator, one end of saidradiator extending at an angle and joining the adjacentwall of thedigester, and upper and lower feed and outlet openings for saiddigester.

2. A vertically disposed digester'having a tapered lower end and upperand lower feed openings, and a centrally disposedvertically extendingradiator in alinement with said openings, the lower end of said radiatorextending at an angle and connecting with the tapered port-ion of saiddigester, whereby to provide a clearance for the lower opening of thedigester.

3. A. digester having a centrally disposed vertically extending steampipe closed at its upper end and provided adjacent its lower end witha'condensation valve, and a vertically extending vent pipe located insaid radiator and being open at its upper end and provided with a valveat its lower end.

4. A digester having an inlet at its upper end an outlet at its lowerend, a vertically extending centrally disposed steam pipe closed at itsupper end and provided with a condensation valve and a steam inlet atits lower end, a centrally disposed vertically extending vent pipe insaid steam pipe, said vent pipe being open at its upper end and beingprovided with a valve at its lower end, spiders for supporting saidsteam pipe in said digester, and spiders for supporting said vent pipein said steam pipe.

in testimony that I claim the foregoing as my own, I have hereto aflixedmy signature in the presence of two witnesses.

GEORGE A. STEBBINS.

Witnesses H. O. Mnrzonu, N. G. BARONE.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. C.

